akkoma/lib/pleroma/web/oauth/scopes.ex
Ivan Tashkinov 81b05340e9 [#1427] Graceful clearance of OAuth admin scopes for non-admin users (no error raised).
PleromaFE and other clients may safely request admin scope(s): if user isn't an admin, request is successful but only non-admin scopes from request are granted.
2019-12-12 16:00:06 +03:00

94 lines
2.5 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.OAuth.Scopes do
@moduledoc """
Functions for dealing with scopes.
"""
alias Pleroma.Plugs.OAuthScopesPlug
alias Pleroma.User
@doc """
Fetch scopes from request params.
Note: `scopes` is used by Mastodon — supporting it but sticking to
OAuth's standard `scope` wherever we control it
"""
@spec fetch_scopes(map(), list()) :: list()
def fetch_scopes(params, default) do
parse_scopes(params["scope"] || params["scopes"], default)
end
def parse_scopes(scopes, _default) when is_list(scopes) do
Enum.filter(scopes, &(&1 not in [nil, ""]))
end
def parse_scopes(scopes, default) when is_binary(scopes) do
scopes
|> to_list
|> parse_scopes(default)
end
def parse_scopes(_, default) do
default
end
@doc """
Convert scopes string to list
"""
@spec to_list(binary()) :: [binary()]
def to_list(nil), do: []
def to_list(str) do
str
|> String.trim()
|> String.split(~r/[\s,]+/)
end
@doc """
Convert scopes list to string
"""
@spec to_string(list()) :: binary()
def to_string(scopes), do: Enum.join(scopes, " ")
@doc """
Validates scopes.
"""
@spec validate(list() | nil, list(), User.t()) ::
{:ok, list()} | {:error, :missing_scopes | :unsupported_scopes}
def validate(blank_scopes, _app_scopes, _user) when blank_scopes in [nil, []],
do: {:error, :missing_scopes}
def validate(scopes, app_scopes, %User{} = user) do
with {:ok, _} <- ensure_scopes_support(scopes, app_scopes),
{:ok, scopes} <- authorize_admin_scopes(scopes, app_scopes, user) do
{:ok, scopes}
end
end
defp ensure_scopes_support(scopes, app_scopes) do
case OAuthScopesPlug.filter_descendants(scopes, app_scopes) do
^scopes -> {:ok, scopes}
_ -> {:error, :unsupported_scopes}
end
end
defp authorize_admin_scopes(scopes, app_scopes, %User{} = user) do
if user.is_admin || !contains_admin_scopes?(scopes) || !contains_admin_scopes?(app_scopes) do
{:ok, scopes}
else
# Gracefully dropping admin scopes from requested scopes if user isn't an admin (not raising)
scopes = scopes -- OAuthScopesPlug.filter_descendants(scopes, ["admin"])
validate(scopes, app_scopes, user)
end
end
def contains_admin_scopes?(scopes) do
scopes
|> OAuthScopesPlug.filter_descendants(["admin"])
|> Enum.any?()
end
end